With a historically large number of key executive positions unfilled nearly six months into President Trump’s term, the White House and members of Congress are pointing fingers at one another over what the White House called the “needless obstruction” of qualified candidates.

The White House and Senate Republicans have slammed Senate Democrats for obstructing the confirmation of Trump’s nominees. Democrats have responded that Republicans control the Senate floor and could bring nominees to the floor and force a vote whenever they choose, and that nominees have lacked proper paperwork.

The confirmation process for Trump’s nominees has dragged, leaving agencies with key positions vacant. As of Monday, the Senate has confirmed 50 of Trump’s nominees.

Using procedural tactics including the filibuster, Senate Democrats have forced Senate Majority Leader Mitch McConnell, R-Ky., to invoke cloture votes — a lengthy process — for most of Trump’s nominees. Cloture votes can stop a filibuster but also require leadership to allow up to 30 hours of debate on nominees, resulting in a time-consuming confirmation process. Democrats have forced cloture votes on 32 of the 50 confirmed nominees as of Tuesday.

The Trump administration blamed Senate Democrats for obstructing qualified candidates, stating that Democrats have invoked “time-consuming parliamentary procedures.” The president chimed in Tuesday on Twitter, writing, “The Senate Democrats have only confirmed 48 of 197 Presidential Nominees. They can’t win so all they do is slow things down & obstruct!”

The Senate Democrats have only confirmed 48 of 197 Presidential Nominees. They can't win so all they do is slow things down & obstruct!

The Political Appointee Tracker, maintained by the Washington Post and the Partnership for Public Service, has a slightly different count, and says Trump has submitted formal nominations for 129 of 564 key positions that require Senate confirmation.

McConnell spokesman David Popp answered repeated questions about why the Senate majority leader had not brought more Trump nominees to the floor by directing Yahoo News to Senate Minority Leader Chuck Schumer, D-N.Y.

“The delay/obstruction questions can best be answered by Leader Schumer and/or other Members of his caucus,” Popp wrote in an email.

Schumer spokesman Matt House directed Yahoo News back to McConnell’s office, stating that the majority leader could move a nomination at any time, and that McConnell had not been prioritizing the nominations.

“He’s just not prioritizing the nomination by not bringing it up on the floor,” House wrote.

The Senate minority leader seemed to both take credit for the stalling tactics and push blame for the delay on Republicans.

Schumer blasted Republicans for the delay in his Monday evening remarks on the floor, telling the White House to “look in the mirror” to see the cause for the delay in nominations.

“No administration in recent memory has been slower in sending nominees to the Senate,” Schumer said. “In the last few weeks, the administration has sent several nominees without all of their paperwork or ethics agreement complete. We can’t go forward until that happens.”

But Schumer’s spokesman referred Yahoo News to the Senate minority leader’s warning to Republicans last month that Democrats would use procedural tactics to fight the GOP health care plan.

“Republicans are drafting this bill in secret because they’re ashamed of it, plain and simple,” Schumer told reporters. “If Republicans won’t relent and debate their health care bill in the open for the American people to see, then they shouldn’t expect business as usual in the Senate.”

The result, according to McConnell’s spokesman, is that Democrats have forced McConnell to invoke cloture votes even for safe, uncontroversial nominees. He cited Monday’s vote on David C. Nye, a nominee for a district judgeship in Iowa. Nye, whose nomination to the same position by President Barack Obama expired before he could be confirmed, faced a cloture vote but cleared it, 97-0.

“This is a textbook move to drag out a nominee far longer than it should take,” Popp said. “And all it took was one Dem to do it, and they did it.”

On the other hand, Schumer’s spokesman pointed to the lack of completed and submitted paperwork for Trump nominees as the reason for the holdup.

In a July 10 email to media, Schumer’s office said that four selections to the Commerce Department were nominated with missing paperwork. Those nominees included Karen Dunn Kelley for undersecretary of commerce for economic affairs and Mark Buzby, chosen to lead the Maritime Administration.

A spokesman for the Senate Committee on Commerce, Science and Transportation, Frederick Hill, told Yahoo News Tuesday that the panel has all the necessary paperwork for all the nominees it has to confirm. Hill said Kelley’s paperwork was submitted June 20, and that Buzby’s was turned in on June 27.

Schumer’s office said it stopped collecting data for the information included in its July 10 email on June 30 — 10 days after the Commerce Department says it received Kelley’s paperwork and three days after it received Buzby’s data.

Senate Democrats have also held up issuing “blue slips,” which signify senators’ approval of a judicial nominee from their home states. Although blue slips are not constitutionally mandated, they are a time-honored Senate tradition.

Two nominees, Judge David Stras, who was picked for the Eighth U.S. Circuit Court of Appeals, and Judge Joan Larsen, who was named to the Sixth U.S. Circuit Court of Appeals, have not had confirmation hearings, even though their nominations were announced May 8.

The Senate Judiciary Committee told Yahoo News Monday that it had not received blue slips from home state senators for Larsen, who is from Michigan, or Stras, from Minnesota, but that their nomination materials had been public for more than a month.

A statement from the office of Sen. Al Franken, D-Minn., said the delay occurred was because the White House broke tradition and did not have a “meaningful consultation” with the senator before announcing Stras’ nomination.

“Because the senator was not meaningfully consulted in advance, and due to the nominee’s lengthy record, Senator Franken is taking care to closely review Justice Stras’ decisions and writings before deciding how best to proceed,” the statement reads.

Similarly, sources familiar with Larsen’s nomination told Yahoo News that the White House broke tradition by failing to consult Democratic Sens. Gary Peters and Debbie Stabenow of Michigan before nominating Larsen. The sources said that Peters’ office requested additional information on Larsen for Peters to review before the senator makes a final decision and submits a blue slip. Stabenow is also reviewing Larsen’s materials, which includes hundreds of pages of documents, a source said.